The processing speed of a computer system is determined by two primary factors, front side bus (FSB) and central processing unit (CPU) speed. Also known as system bus speed, front side bus speed is the speed at which the CPU communicates with memory and other components on the system. Front side bus speeds is determined by a clock setting, while CPU speed is typically determined by a multiplier of that same value. For example, a processor having a listed speed of 1.0 Ghz may use a system bus of 100 Mhz and a multiplier of 10 (10×100 Mhz=1000 Mhz or 1.0 Ghz).
The “listed” processor speed refers to the intended processing speed by the processor's manufacturer. Overclocking is one method of boosting the processing speed of a computer component with a clock rate higher than the clock rate designated by specifications. However, if done arbitrarily, over d locking can be dangerous because of the increased thermal output of the processor and other components on the system. Overclocking may shorten the lifespan of the processor, as it exceeds the temperature envelope it was designed to work within, and in the worst case, the processor may be permanently damaged. Controlling the thermal levels of the integrated circuits and the computer system in general are important for maintaining the stability and longetivity of the components. Typically, a thermal sensing device is built into the CPU that allows the motherboard to measure the temperature of the CPU, and other critical zones in the system, so that system fans of the thermal control systems can try to counter the rising temperature. Such mechanisms may include fan speed, thermal throttling (reduction of system speed), or system shutdown.
One problem with motherboards, particularly retail motherboards for computer systems, is that they are designed without a specific idea of what kind of thermal environment the motherboard will be used in (e.g., size of chassis, number of fans, cooling options, ambient temperature, etc.). Depending on the cooling solutions integrated into the motherboard, the processors may operate at speeds greater than their listed speeds in a safe manner if the thermal conditions are maintained below harmful levels.